28 U.S.C. § 1583: Counterclaims, cross-claims, and third-party actions

In any civil action in the Court of International Trade, the court shall have exclusive jurisdiction to render judgment upon any counterclaim, cross-claim, or third-party action of any party, if (1) such claim or action involves the imported merchandise that is the subject matter of such civil action, or (2) such claim or action is to recover upon a bond or customs duties relating to such merchandise.